Lubricating composition



Patented July 2 5, 1944 LUBRICATING COMPQSITION Harold M. Fraser and Thomas Audley Maxwell, New Orleans, La., asslgnors to International Lubricant Corporation,

corporation of Louisiana New Orleans, La., a

No Drawing. Application February 11, 1941,

' Serial No. 378,444

1 Claim.

'Ifhe present invention is directed to the treatment of lubricating oils and lubricant compositions to reduce the formation of sludge and of corrosive-forming acids during the time the lubricating oil or composition is used in the combustion engine cylinder. high pressures in the combustion cylinder, the

.amount of sludge derived from the lubricating oil or composition has greatly ,increased and, therefore, it has become of great importance to devise a remedy to inhibit the production of sludge. When lubricating oils or lubricant compositions containing mineral oils are subjected to the conditions prevailing in the cylinders of internal combustion engines, deterioration occurs With the increase of from this standpoint to inhibit the formation of sludge and acids in the lubricating oil.

In accordance with the present invention, lubricatingmineraloils and lubricating composi tions. containing mineral oils are stabilized against oxidation under conditions prevailing during combustion in the engine cylinder of .an

' internal combustion engine by having present in due to thermal action and oxidation in the presence of a diversity of metals which may be in a massive state or in a finely divided Lstate, or in both. This :deterioration is due to the formation of carbonaceous and coke-like materials and a variety of oxygenated products as well as degradation, interaction, condensation, polymerization, dehydrogenation, and dehydration products. Such action is evidenced by impairment of color of the lubricating material, carbon formation, sludge formation, acid formation, and/or viscosity increase. The relative extent of each action varies with the type of the lubricating oil or composition and the process used in producing and refining said lubricating oil or composition.

Further, various materials added to the oil for specific purposes, as for example, detergents for Diesel lubrication, or various extreme pressure additives, may greatly affect the extent'of each action. More specifically, in modern engines, due to the high pressure. and high operating temperature, it has been ascertained that it is desirable to replace the hitherto-used babbitt bearings with other-alloy bearings such as cadmium, silver-cadmium, nickel or copper-lead. In other words, the babbitt bearings have been found'to wear and deteriorate in tensile strength, and have therefore been replaced to a substantial extent by new bearing alloys. These new bearing alloys are rather sensitive to the acids formed in the lubricating material, oil or composition, said acids functioning to corrode the bearings. Stated differently, lubricating materials such as mineral oils or mineral oil compositions which have not been inhibited relative to oxidation exert a corrosive action on the bearings.

It has also been ascertained that some of the alloy constituents of the new bearing alloys func tion as oxidation catalysts, that is, function to promote the formation of acids and sludge in the lubricant a small amount of a phenylene diamine. The addition of said phenylene diamine improves the stability of the composition towards the action of oxygen'or oxygen bearing gases atelevated temperatures, either in the presence of metals, metal compounds; vor soluble metal salts generally present in the operating cylinders of internal combustion engines.

The present invention is particularly applicable to, petroleum hydrocarbons and especially to representative oils from Pennsylvania, the Mid- Continent, and to Gulf Coastal crudes. Solvent treated oils and compositions containing the same, and petroleum hydrocarbons with, additive ingredients, may also be treated in accordance point depressors, viscosity index improvers, detergents, extreme pressure additives, oiliness adthe mineral oil. Therefore, it becomes necessary with the present invention, and the so-treated oils are stable towards oxidation. There may be present in the lubricating oil or composition pour ditives, phosphite esters, and other organic phosphorous compounds, sulfurized fixed oils, anticorrosives, metal poisoners, and other oxidation inhibitors.

It has been discovered that the phenylene diamines are soluble in lubricating petroleum hydrocarbons and mineral oil in amounts varying between .01 to .1% based on the weight of the hydrocarbon material treated, and further, it has been found that these small amounts are sufficient toinhibit against oxidation. More specifically, it has been discovered that the addition of .03 to .05% of the phenylene diamines based on the weight of the lubricating oil represents the optimum amounts for the stabilization of most lubricating oils. It has also been ascertained that certain oils may be beneficially stabilized by having more than .1% of the phenylene diamines present. ,The discovery has been made that it is not only the phenylene diamine which goes into solution which is eflective to promote and achieve stabilization, but that undissolved phenylene diamine dispersed through the lubricating oil or composition also effects stabilization. More specifically, up to 1% of phenylene diamine in dispersion, in some cases, promotes stabilization,

It has also been discovered that the phenylene diamines not only function as anti-oxidant and anti-sludge forming agents, but also the phenylene diamines do not to any material extent affect the viscosity of the so-treated oil. This may be due to the fact that the phenylene diamine prevents the formation of oxidation products in the oil or composition being treated. It may be stated that it is highly desirable to maintain the original viscosity of the lubricating oil or composition which is being inhibited against oxidation and the formation of sludge.

It has also been discovered that the antioxidation capacity of certain well-known inhibitants of lubricating oil may be considerably improved by mixing said agents with a small proportion of phenylene diamine, as' for example .03 to .05% and, in some cases, up to -.1%. In other cases, the phenylene diamine may be mixed 'with other inhibitors in an amount up to 1%.

For example, there may be added to the lubricating mineral oil a mixture of para-amino-phenol and anthranillcacid and any of the phenylenediamines to produce a composite inhibitor of oxidation and a preventative for sludge formation. More specifically, the mineral oil may contain 0.5% of para-amino-phenol, .05% of any of the phenylene diamines, and .1% of anthranilic acid. In the alternative, there may be added to the mineral oil a mixture of .05% of para-aminophenol and .05% of any of the phenylene diamines. Or there may be added to the mineral oil .l% of anthranilic acid and .05% of any of the phenylene diamines. While these are the preferred percentages, the latter may be considerably varied.

v In the more specific aspect of the present invention, it has been ascertained that when heavy metal organic salts have been added to lubricating oils to impart detergent characteristics thereto, the usual undesirable catalytic effect thereof on the oxidation of the lubricating oil can be inhibited by adding a small quantity of a phenylene diamine as, for example .03 to .05% or even .1% or up-to 1%. The phenylene diamines are single to a boiling point of 267 C. for the para. This lower melting pointobviates the possibility of formatior of solid crystals by portions of the material driven from the oil at higher temperatures, a contingency which the higher'melting point of p-phenylenediamine might occasion. The lower melting point and higher boiling point of m-phenylene diamine also facilitate incorporation and retention of the compound.

The results obtained by adding phenylene diamine to lubricating oils are set forth in the following tables. In'the experiments, the results of which are tabulated. in said tables, the oxidation resistance of the oil was determined by bubbling oxygen through samples of oil at controlled temperatures in the presence of metallic, copper.

Copper was used since it is actively catalytic for.

and is the most generally used catalyst for oxidation of lubricating oils. Viscosity determinations on the oil were made before and after blowing. Neutralization numbers and naphthainsolubles were determined at intervals during and at the completion of blowing. Specifically: 400 c. c. of I the oil under test was placed in a glass test tube 50 x 450 mm. The tube was immersed in an oil bath at 300 F. to a depth such that the bath level was well above the surface of the oil under test. 18' of freshly polished No. 14 gauge copper wire, wound in a helix of 40 mm. diameter, was placed in the tube and commercial quality oxygen was admitted thru a 6 mm. glass tube extending to /4" from the bottom. An oxygen flow of 10 liters per hour was maintained by the use of a needle valve and flow-meter in the line from the oxygen storage cylinder.

A c. sample was withdrawn at 24 hours without in r'rupting blowing and the entire sample was withdrawn at 48 hours.

ring compounds having a benzene nucleus to by the nature of the base oil, the additives which may be present therein, and to some extent by the physical characteristics of the phenylene diamines themselves. O-phenylene diamine is a colorless solid melting at 140 C., and boiling at 252 C.; m-phenylene diamine is a colorless solid melting at 63 C. and boiling at 287 C.; pphenylene diamine is a colorless solid melting at 140 C. and boiling at 267 C. All of these phenylene-diamines are sparingly soluble in the petroleum oils or hydrocarbons herein set forth. The meta and para phenylene diamines are usually preferred in carrying out the present invention in View of the fact that they boil at higher temperatures. The preference is governed not so much by superiority of the meta compound in stabilization, but rather by the physical properties of the. meta as compared to the para. The meta has a-melting point as shown above of 63 C. as compared to 140 C. for the para, while having also a boiling point of 287 C. as compared 76 The neutralization number set forth in the following tables representsthe milligrams of potassium hydroxide necessary to neutralize one gram of oil, and was determined on the sample withdrawn at 24 hours, and on-the oil after 48 hours. This determination was made'in accordance with the method developed by Fenske, Stevenson et al., and reported in a paper read before the Petroleum Division of the American Chemical Society, Detroit, 1940. The neutralization number was determined in 'each case in the following manner: .5 grams of the oil was dissolved in 50 c. c. of. half and half benzene-butanol mixture, ,fluorescein and methyl red solutions were added as indicator, and the solution was titrated in a dark room with sodium butylate to a fluorescent endpoint, illuminating from the side with a point source of light.

The naphtha insolubles or sludge shown in the following tables represents milligrams of sludge per 10 grams of oil and was determined by diluting 10 grams of the oil with c. c. of A. S. T. M. precipitation naphtha, shaking and allowing the resulting solution to settle for three hours. The precipitate was collected on an asbestos mat in a Gooch crucible, dried at 300 F. and weighed.-

In order to ascertain the effect of the phenylene from Mid-Continent crude and blends of the two to, give an S. A. E. 30 paraifn oil were oxidized under the test conditionsflaithout additives and with specified proportions of phenylene diamines. Y

The phenylenediamines used were of commercial quality, currently available, and the proportion of the other isomers in each was not determined. M shown in Table I concentrations as low as .01% were very efiective, while 1%,

hours; the neutralization number for the twentyfour hour period and for the forty-eight hour period, and the percentage of viscosity increase at 210 F. Saybolt Universal after a forty-eight representing 5 hour oxidation test.

Table I Neutralization Per cent Mg spludge number viscosity Oil Additive increase at 210 F 24 hr. 48 hr. 24 hr. 48 hr. 48 hr Porafiin neutral S. U. V. 47 at 210 F None 65 104 .36 3. 2 4 Do 05% m-phenylenediamine. 6 8 .07 l4 Paralfin Bright Stk S. U. V. 121 at 210 F None 7 74 8. 2 6.5 45 Do 4 14 .58 6 Parsfiln S. A. E. 30. one 59 121 2.0 3. 2 16 Do .01% m-phenylenediamine... 3 35 .34 I 93 2 Do 03% ln-phenylenediaminc... 4 8 .24 .41 0 Do. .05% m-phenylenediamine... 6 8 07 21 0 Do .l0% rn-phenylenediamine 5 8 .07 0 Do 1.0% n -phenylenediamiue. 11 15 .07 .07 0 Do 03% o-pheuyl0nedi0mine 3 11 14 .50 3

Do .057 o-phenylenediamine 3 10 .21 .36 1. 5 Do .10 0 o-phenylenediamino. 5 ll 29 46 2 Do .03% p-phenylenediamine. 3 3 .07 14 0 Do .05% p-phenylenediamine. 4 5 .07 14 5 Do .l0% p-phenylenedinmine. 6 8 07 14 I .3

a saturated solution with the balance dispersed in finely divided form, was remarkably effective. When'treated with 03% or more of phenylene diamine, the oil left no appreciable lacquer on the walls of the glass tube or on the copperwire,

In another experiment, Gulf Coastal and sol.- vent treated Mid-Continent oils were subjected to test without additives and with specified proportions of m-phenylenediamine. The additive was beneficial in all cases. Lacquer formation, conspicuous with the untreated oils, was so reduced as to be scarcely detectable, while sludge formation, acid formation, and viscosity increase were greatly reduced. The results of these experiments are set forth in Table II which follows:

Table II Neutralization Per cent Mg Sludge number viscosity Oil Additive increase at 210 F.

24 hr. 48 hr 24 hr. 48 hr. 48 hr.

Pennsylvania S. A. E. 30 None 57 93 2. 9 4. 7 16 o 05% m-phenylcnediamine 10 14 14 .50 0 Gulf Coastal S. A. E. 30. None 163 1.0 l. 7 12 o 05% m-phenylencdiamine 26 62 .36 36 2 Solvent treated S. A. E. 30 from M id- None 47 201 2. 5 5. 6 16 D .05% m-phenyleuedian1inc 19 45 .22 1. 7 4

In the following tables there is set forth the particular kind of mineral oil used with and without certain'anti-oxidants; the amount of sludge produced in twenty-four hours and forty'eight In another series of experiments the phenylene diamines were added to oils containing several commonly used additives. The particulars thereof appear in Table III.

Table III Neutralization Per cent Add 1 M 81 Mg sludge number viscosity Oil it vc increase catalyst at 210 F.

- 24 hr. 48 hr. 24 hr. 48 hr. 48 hr.

Peraflln B. A. E. 30+E. P. Diesel additive None Cu 36 1.7 2. 5 10 o .05% m-phenylenediamine Cu 9 10 07 29 0 Gull Coastal S A. E. 30+E. P. Diesel additive one Cu 221 380 3. 4 5. 3 45 Do .05% m-phenylenediamine; Cu 25 61 33 57 5 None Cu 68 133 2. 5 4. 3 14 05% m-phcnylenediamine... Cu 8 11 .07 36 7 None Cu 1 25 28 l. 0 5

.057 m-phen enediammc... Cu 6 7 10 .51 6 None Cu 14 13 .26 .36 3 05% in Cu 10 9 17 36 3 None Cu 45 2.0 2. 7 16 05% in Cu 6 7 09 7 None. Cu 46 98 l. 9 2. 7 16 .05% in Cu 7 7 .07 22 -3 None. Cu 21 73 87 2. 4 10 05% m-phcnylenediamin Cu 21 42 .50 72 4 None Cu 59 2. 0 3. 3 13 Do .059 m-phenylcnediumine... Cu 22 37 39 .64 3 Peraflin S. A. E. 30+.1% anthram 0 acid None Cu 3 9 .22 .40 4 o 05% m-phenylencdiarnme Cu 4 5 .07 22 1 Paraflin S. A. E. 30+.05 p-aminophenol None Cu 4 l7 22 58 5 Do 05% m-phenylcnedmmme... Cu 8 ll 27 1 While the combination was not as effectiv for oxidation inhibition in some cases as was the phenylene diamine alone, the phenylene diamine depressors are those produced by chlorinating waxy hydrocarbons and then condensing the chlorinated wax either alone'or with an aromatic material in the presence of a catalytic agent such as aluminum. chloride or other Friedel-Crafts type condensing agent such as zinc chloride or ferric chloride. As an example of this type of compound, Parafiow, a product of the Standard Oil Co'., was added to an S. A. E. paraffin oil, and the composition tested with' and without added phenylene diamine. The present invention may be carried out using other pour point depressors as, for example, the synthetic oil produced by a low temperature aluminum chloride condensation of chlorinated paraffin wax and naphthalene.

During recent years, certain types of high molecular weight polymeric linear chain compounds have been effectively used toraise the viscosity index of mineral oils. For example, high molecular weight. hydrocarbons obtained by polymerizing iso-olefines may be added to lubricating oils with the result that the temperature-viscosity curve of the oil is found in many cases to be remarkably flattened. For example, polymerized isobutylene has been found very useful in raising the viscosity index of lubricating mineral oils. When 100 parts of liquid isobutylene is treated with 1% part of boron fluoride, the isobutylene being cooled by a bath of carbon dioxide at 80 below zero 0., polymerization of the isobutylene occurs, the reaction product having a mean molecular weight of 3500. As an example of this popular type of additive, mention may be made of Paratone which is a product manufactured by the Standard Oil Development Co. Paratone was added to an S. A. E. paramn oil, and the composition tested with and without phenylene diamine. Chlorinated organic compounds have been widely used as additives to impart high fihn strength characteristics to lubricating mineral oils. property of imparting detergency and oiliness characteristics to the composition. For example, ther may be incorporated with a mineral oil base chlorinated ring compounds, as for example mono-chlorbenzene or chlorbenzene, chlomaphthalenes, chlordiphenyls and the like. Further, certain oxygen containing organic ring compounds which have been chlorinated have been found useful for thin-film" lubricating purposes.

Many of these compounds are manufactured by the Lubrizol Sales Corp. Anglamol 714, a product of the Lubrizol Sales Corp. was added to an S. A. E. 30 paraffin oil, and the composition tested both with and without phenylene diamine. Anglamol 714 was also added to an S. A. E. 30 PaleCoastal oil and the composition tested both with and without added phenylene diamine.

Sulfurizcd animal and vegetable oils have been Some of these compounds have the added widely used as additives to impart film strength and/or anticorrosive properties to lubricantcompositions. As an example of this class, a sulfurized sperm oil containing 10% by weight of sulfur in combination was added to an S. A. E. 30 paraflin oil and the composition tested with and without added phenylene diamine.

Aryl and alkyl phosphite esters have been widely used as additives to impart anticorrosive,

E. P., or antioxidant properties to the composition. As an example-of this type tri-m-cresylphosphite was added to an S. A. E. 30 paraflln oil and the composition tested with and without added phenylene diamine. v

Heavy metal salts have been extensively used to impart detergent qualities to oil for Diesel lubrication. Many of these salts are capable of furnishing the necessary detergency but have undesirable catalytic effect on oxidation of the oil to which they are added. As an example of this type of compound the nickel salt of hydrogenated abietic acid was added to an S. A. E. 30 paraffin oil and the composition tested with and without added phenylene diamine. v

As stated, the phenylene diamines are soluble in lubricating mineral oils in an amount varying between .01 to .1% based on the weight of the mineral oil treated. When the amount of phenylene diamine is greater than the above, it is desirable, if not necessary, to disperse th phenylene diamine in the mineral oil. Any suitable dispersion agent may be used, but it has been found that alcohol, the ethanolamines, and particularly tri-ethanolamine and butyl carbitol function very satisfactorily as dispersion agents.

It has been found that when a composite antioxidant and anti-sludge forming medium is added to the lubricating mineral oil which already contains other anti-oxidants and anti-sludge forming agents, the phenylene diamine functions to increase the activity of the primary anti-oxidant and anti-sludge forming agent.

Referring to Table III, the expression Alox No.

350 defines the methyl ester of the material consisting mainly of fatty, hydroxy, keto and keto hydroxy acid, together with some unsaponifiable alcohol and alcohol ketone. This compound is made by controlled oxidation of a fraction of Pennsylvania petroleum, and the acids formed range from those containing 5 carbon atoms to 35 carbon atoms.

What we claim is:

A lubricating composition stabilized against oxidation under temperature conditions prevailing during combustion in the engine cylinder of an internal combustion engine, said composition containing as its principal lubricating constituent a major portion of a mineral lubricating oil having incorporated therein an anti-oxidant and anti-sludge forming agent, comprising a primary phenylene diamine, and an ethanolamine acting as a dispersion agent for the phenylene diamine.

HAROLD M. FRASER. THOMAS AUDLEY MAXWELL. 

